HESI A2 Physics

Correct Answer: D

Rationale: To calculate impulse, we use the formula Impulse = Change in Momentum. First, calculate the initial momentum: initial momentum = 10 kg * 5 m/s = 50 kg⋅m/s. Then, calculate the final momentum: final momentum = 10 kg * 15 m/s = 150 kg⋅m/s. The change in momentum is final momentum - initial momentum = 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choice D is correct as it correctly represents the impulse value. Choices A, B, and C are incorrect as they do not accurately reflect the calculated impulse value.

Correct Answer: A

Rationale: The correct answer is A: Pressure. Pumps increase fluid pressure by adding energy to the fluid. When the fluid flows through the pump, it gains kinetic energy which is then converted into pressure energy. Choice B is incorrect because pumps do not primarily aim to increase velocity only. Choice C is incorrect as while pumps do increase both pressure and velocity, the primary goal is to increase pressure. Choice D is incorrect as pumps are specifically designed to increase either pressure, velocity, or both, depending on the application.

Correct Answer: C

Rationale: The correct answer is C: Hydrogen gas. This is because gases are highly affected by changes in temperature due to their particles having more kinetic energy. When temperature increases, gas particles move faster, increasing pressure. Conversely, when temperature decreases, gas particles move slower, decreasing pressure. In contrast, liquid nitrogen (choice A) and salt crystals (choice B) are not as affected by temperature changes due to their stable structures. Iron filings (choice D) are also not significantly affected by temperature changes as they are solid and have a fixed shape and volume.

Correct Answer: D

Rationale: To calculate work, we use the formula W = F*d, where W is work, F is force, and d is distance. In this case, the force is 15 N and the distance is 3 m. So, W = 15 N * 3 m = 45 N⋅m. Therefore, the correct answer is D. Choice A is incorrect as it incorrectly calculates work by dividing force by distance. Choice B is incorrect as it only provides the correct unit for work, not the actual calculation. Choice C is incorrect as it incorrectly multiplies force and distance to get the wrong result.

Correct Answer: C

Rationale: The correct answer is C: Heat. When current flows through a circuit with resistance, the resistance causes collisions between electrons and atoms, resulting in energy loss in the form of heat. This is known as Joule heating. Light (A) is not typically generated by electrical resistance, and sound (B) is not a common form of energy dissipation in circuits. Mechanical work (D) involves movement and is not directly related to energy dissipation due to resistance.